The recent gulf BP oil spill is undoubtedly the worst man made oil spill in US history, dwarfing even the notorious Exxon Valdez spill in 1989. Oil spill clean up workers tend to have a myriad of health effects, such as skin, lung, and neurological problems. Inflammatory disorders of the skin are almost ubiquitous in the work place. Up to 50% of workers world-wide suffer from dermatitis at any time (Diepgen, 2007) and of reported occupational injury associated with workman's compensation in the US, contact dermatitis ranks second most prevalent overall, affecting workers in all industries (Beltrani, 2003). Dermatitis is divided into two main manifestations, that of irritant and allergic. The major difference between these pathologies is often described as whether the disease is of immunological origin (allergic) where T Cells are involved; or of non-immunological origin (irritant) where physical damage is thought to be the major initiating event. Since a very recent report found that oil samples from the Gulf Oil Spill were indeed a skin irritant, the focus of the first specific aim of this application will be to define the associated inflammatory response. Mice will be exposed to fresh and weathered oil or controls for seven days. Skin samples will be assessed for inflammatory cytokine expression, and inflammatory cell infiltration by histology and flow cytometry. The second specific aim will attempt to identify what components of spilled crude oil might be associated with dermatitis. First, skin of oil exposed mice will be extracted and petrochemicals will be determined by GC-MS analysis. There is also the possibility that microbial contamination of oil may lend itself to irritancy or allergy. Thus, marine bacteria populations will be assessed and identified from oil samples by rRNA analysis. The ultimate goal of this project is to identify the nature of oil spill dermatitis, allowing for rational risk assessment and exposure guidelines. Since little is known concerning oil spill health effects, these data will also aid in the further mechanistic investigations of this pathology by providing direction for future research.